/*
 *    Copyright 2008-2009 The PoCo Team
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package com.asemantics.poco.services;

import java.io.IOException;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.nio.charset.Charset;

import javax.ws.rs.WebApplicationException;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.MultivaluedMap;
import javax.ws.rs.ext.MessageBodyWriter;

import com.asemantics.poco.Response;

/**
 * 
 * @author Simone Tripodi
 * @version $Id: AbstractPoCoBodyWriter.java 269 2009-12-21 11:40:03Z simone.tripodi@gmail.com $
 */
abstract class AbstractPoCoBodyWriter implements MessageBodyWriter<Response>{

    private static Charset UTF_8 = Charset.forName("UTF-8");

    /**
     * {@inheritDoc}
     */
    @Override
    public long getSize(Response response,
            Class<?> type,
            Type genericType,
            Annotation[] annotations,
            MediaType mediaType) {
        return -1;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isWriteable(Class<?> type,
            Type genericType,
            Annotation[] annotations,
            MediaType mediaType) {
        return Response.class == type;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void writeTo(Response response,
            Class<?> type,
            Type genericType,
            Annotation[] annotations,
            MediaType mediaType,
            MultivaluedMap<String, Object> httpHeaders,
            OutputStream entityStream) throws IOException, WebApplicationException {
        this.writeTo(response, type, genericType, annotations, mediaType, httpHeaders, new OutputStreamWriter(entityStream, UTF_8));
    }

    /**
     * Write a {@link Response} to an HTTP response.
     *
     * @param response the response to write.
     * @param type the class of object that is to be written.
     * @param genericType
     * @param annotations
     * @param mediaType
     * @param httpHeaders
     * @param entityWriter
     * @throws IOException
     * @throws WebApplicationException
     */
    protected abstract void writeTo(Response response,
            Class<?> type,
            Type genericType,
            Annotation[] annotations,
            MediaType mediaType,
            MultivaluedMap<String, Object> httpHeaders,
            Writer entityWriter) throws IOException, WebApplicationException;

}
